Declare C, C++, and Objective-C support for sourcekit-lsp

[10000DOO]

Problem

In mixed Xcode projects (Swift + Objective-C), sourcekit-lsp only activates for .swift files because this extension only declares Swift as a supported language.

This means:

• .m / .mm / .h files get no LSP support from sourcekit-lsp
• Cross-references between Swift and ObjC code don't work (e.g. jump-to-definition from Swift → ObjC class fails)

Solution

sourcekit-lsp already handles C, C++, Objective-C, and Objective-C++ internally via its embedded clangd integration. The server is ready — Zed just isn't routing those file types to it.

This PR:

1. Migrates from the deprecated language field to the languages array
2. Adds Objective-C and Objective-C++ language definitions with tree-sitter-objc grammar
3. Routes all 5 languages to sourcekit-lsp

This matches how the official VSCode Swift extension already works:
https://github.com/swiftlang/vscode-swift/blob/fd00b062831a3919b07071b8b5f5e6a5690c6e8a/src/configuration.ts#L153-L157

Also, xcode-build-server already generates buildServer.json with all 5 languages declared — so the server side is already set up for this.

Changes

extension.toml:

# Before (deprecated single-language field)
[language_servers.sourcekit-lsp]
language = "Swift"

# After
[language_servers.sourcekit-lsp]
languages = ["Swift", "C", "C++", "Objective-C", "Objective-C++"]

[language_servers.sourcekit-lsp.language_ids]
Swift = "swift"
C = "c"
"C++" = "cpp"
"Objective-C" = "objective-c"
"Objective-C++" = "objective-cpp"

[grammars.objc]
repository = "https://github.com/amaanq/tree-sitter-objc"
commit = "181a81b8f23a2d593e7ab4259981f50122909fda"

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[10000DOO]

@cla-bot check

[cla-bot]

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[MrSubidubi]

Thanks for this and sorry for the slow reponse!

I removed the additional language definitions for now given our extension publishing prerequisites - people will need to install the corresponding extension for Objective-C this way, but that should still make the language server work with that.

Will leave you a few days to comment on this, otherwise happy to merge!

[10000DOO]

Thanks for the update, and no worries about the timing!

That approach makes sense to me — requiring the separate Objective-C extension is a fine trade-off as long as the language server still works. Everything looks good on my end, so please feel free to merge whenever you're ready.

Thanks again for your work on this!

[MrSubidubi]

No problem, thank you for getting the PR up in the first place!